Collapsible loop aerial



July 20, 1926.

M. MATHIESEN COLLAPSIBLE LooP AERIAL File d May 29, 1925 2 sheets sheet 1 efmfanff" u Marius Maf77i& fl

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July 20 1926. 1,593,538

M. MATHIESEN COLLAPSIBLE LOOP AERIAL Filed May 294 1925 2 Sheets-Sheet 2 (L 72 van W Marius Maffn'esq'n Patented July 20, 1926.

IVIARIUS MATHIESEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO MATHIESEN-SANDBERG COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

COLLAPSIBLE LOOP AERIAL.

Application filed May 29, 1925. Serial No. 33,684.

My invention relates to improvements in loop aerials and has special reference to loop aerials which are collapsible to a minimum compass for transportation and storage and which have the loops arranged in an inner and an outer series of turns.

This present invention is an improvement on my improved collapsible aerial described and claimed in my co-pending application filed April 13, 1925, S. N. 22,746, and the object is to provide simple means for retaining the inner and outer series of turns, in which the aerial is formed, in their proper relative positions.

My invention relates particularly to improved forms of cross pieces carried by the arms of the collapsible frames, which cross pieces are so formed, arranged, assembled and set, that they serve to assist in forming the loops and retaining the turns thereof in the desired relations to each other.

. For a clear understanding of my invention, attention is directed to the accompanying drawings, forming part of this specification and in which y Figure 1, is a view in elevation of a col lapsibleloop aerial, having cross or wire supporting arms made in accordancewit-h my invention;

Figure 2, is a side View, partly broken away, of one of the cross arms;

Fi ure 8 is a sectional view of the arm,

on the line 3-3 of Figure 3;

Figure 1, is a view similar to Figure 2, showing a'slightly different form of cross arm;

Figure 5, is a section on the line 5 5 of Figure 1;

Figure 6, is a sectional View of another form of cross-arm on the line 66 of Figure 7;

Figurel', is a sectional view on the line 77 of Figure 6;

Figure 8, is a side elevation of another form of cross-arm;

Figure 9, is a sectional view on the line 9-9. of Figure 8; i

Figure 10, is a side elevation of the outer end of one of the arms of the frame equipped i with another form of cross-arm; and

Figure 11, is a vertical section on the line 1111 of Figure 10.

In said drawings, 1 representsa collapsible frame having a mast, comprising a lower section 2 and an upper section 3. At the top of the lower section are hinged two arms l, 4 adapted to be swung out to horizontal position to extend the frame or to be swung in against the lower part 2 of the mast to collapse the frame. The upper part 3 is adapted to telescope down within the lower part 2 when the frame is Collapsed. The lower end of the lower part 2 of the mast, the upper end of the upper part 3 of the mast and thefree ends of the arms at all carry cross pieces or arms 5, formed for receiving the turns of the aerial wire 6 and retaining the turns in an outer series of turns 7 and an inner series of turns 8.

Each of thecross pieces or arms 5 consists of a fiat piece of insulation material. such as hakelite or some similar product adapted to be secured rigidly in position in laterally extending relation upon the ends of the several parts of the frame. In the form of cross piece shown in Figures 2 and 2-3, the cross-arm is provided with a series of slots 9 in which the turns of the inner series 8 of the coil are wound, beginning at one end and winding across until allof the slots have one turn in them. For receiving and retaining the turns of theouter series in position I provide a central longitudinal slot or groove 10 in the outer edge of the arm 5 and adapted to receive a strip of insulation material provided. in its outer edge with wire receiving slots or notches 12.

These notches 12, as shown in full lines, are

preferably arranged transversely midway between the notches 9. 'But, as indicated in dotted lines, they can as readily be arranged in alignment with the notches 9. The strip 11 is preferably glued in place and when thus placed stops off or closes the slots 9 and thus prevents the escape of the inner turns, even should they become loose I on the cross-arms.

Instead of winding the outer series of turns 7 in shallow notches, as shown in Fig ures 2 and 3, I sometimes wind the outer series directly upon the outer edges 13 of edge of the arm When the spacingstrip is used in this manner the turns of the out or layer, as vell as the turns of the inner layer, are held against escape, even though they should become loosened.

Instead of cutting the groove for the insertion of the strips 11 or 14;, I sometimes clamp the turns of the outer series upon the outer edge ot the arms 5 by means of a clamping strip 16 ot' table insulalion material, as shown in I ires 8 and 9. its in the term shown in Figures a and 5, I wind the outer series directly upon the outer edges of the arms 5 and then, I secure the strip ll) upon the outer edge by screws "l7, lirst providing; the inner edge o'l the strip '10 with shallow notches 18 to receive the wires 7 A very simple means oi separating the inner from the outer layer is that shown in .liigures (i and 7, wherein the edge of the arm is provided with the relatively deep notches 9, asshown .in Figure 2, and a longitudinal central slot or -oove 19 is cut in the outer edge, similar to the slot it). After the inner series is wound I then lay a small rod-like strip otinsulation material 20 in the bottom of the groove 19, thus providing a bearing to receive and support the turns ot the outer series. It will be noted that in this form each slot 9 contains a turn of an inner series and also a turn oi an outer series.

It will also be noted that in each instance the turns of the outer series are spaced radially from the turns of the inner series, that in some forms the turns of the outer series may have any desired relation longitudinally of the arm in reference to the inner turns and that in others the transverse relation of the outer turns to the inner turns is predetermined by the arrangement of the openings for receiving the turns.

I preferably complete the winding of the inner layer, then carry the wire bacl; to the beginning end of the arms and wind on the outer layer, but in some forms this manner of winding is not necessary, as it will be evident that in the forms shown in Figures 4:, t3 and 8 the turns could as readily be wound in what is termed the banking form. In other Words, beginning at one end of the several arms the wire could be wound successively to form an outer turn, then an inner turn, and so on across the arms. Sue winding has some advantage regarding self inductance and the lori'ns indicated are particularly adapted for this style of winding.

In Figures 10 and 11 I have shown still another form of cross-arm which serves to hold the turns oil the loop in two series, one within the other. In this form I provide a cross piece 21, similar to the cross piece already described except that instead of being provided with deep notches to receive the first or inner series of turns I provide it with shallow notches 22 spaced longitudinally ot the member and adapted to receive and properly space the inner series 8. I secure this cross piece in a central slot 23 provided. in the outer end ol the frame arm, preferably by fasteners For the outer series of turns 7 I provide a semiul section equal in length to the arm 91 and provided in its outer edge with a series cl notches 2:; to receive the outer turns '7. Th s second part or section is (it proper width so that when the notches 26 are made deep enough to properly receive the turns 1' and tliey are wound in the notches against the bottoms of the Ji'iotches the inner and outer turns will be properly spaced. This second sertion or part is also received in the slot 231 in the arm and is preferably secured in position, with its inner edge against the outer edge of the main part 21, by fasteners :l'i'. It will be noted that this manner of making up the cross-arm is very simple and. eii'ective. In making up such an aerial I lirstwind on the inner series oft turns and then I secure the several outer parts in position and then wind on the outer turns.

The double winding has been adopted so as to be able to reduce the overall (lll'llOIl: sions of the device and yet be able to wind on an equal number of feet of wire.

I do not herein claim broadly .the inserted wire retaining strip, such forming a feature of my co-pending application S. N. 104,694, filed April 26, 1926.

As many modifications of my invention will readily suggest themselves to one skilled in the art, I do not limit my invention to the specific details of construction herein shown and described.

I claim 1. The combination with a collapsible frame for a loop aerial, of cross members carried by the ends of the frame members, the cross members having; openings "for re ceiving and holdinc an inner series ol. turns of wire and a strip of insulation material tl or securing a second series of turns on said cross members, spaced llt\\'&il'(ll from the inner series.

2. The combination with a collapsible frame for a loop aerial, of cross members mounted atthe outer ends of the frame members, the cross members proviced with a series of slots for laterally spacin an inner series of turns of wire and cross member on tensions carried by said members, and said extensions having notches :tor laterally spacing; and securing a similar outer series of turns.

In a device of the kind described, cross members for spacing the turns of wire, said cross members having a series of relatively deep notches in their outer edges for laterally spacing the turns of wire of an inner series, the notches of each member being closed by a strip of insulation carried thereby and a second series of turns laterally spaced by said strip.

4. In a device of the kind described, cross members for spacing the turns of Wire, each said cross member having a series of relatively deep notches for spacing the turns of wire of an inner series, an insulation strip carried by each cross member and provided With a series of notches for laterally spacing an outer series of turns.

5. In a device of the kind described, cross members for spacing the turns of Wire, each said cross member having a series of relatively deep notches for spacing the turns of Wire of an inner series, each cross member having a longitudinal slot in its outer edge, an insulation strip carried in said slot and serving to laterally space a second series of turns spaced outwardly from said inner series.

6. In a device of the kind described, cross members for spacing the turns of Wire, each said cross member having a series of relatively deep notches for spacing the turns of Wire of an inner series, each cross member having a longitudinal groove in its outer edge, an insulation strip mounted in said groove and provided With notches for laterally spacing the turns of an outer series.

7. In a device of the kind described, cross members for spacing the turns of Wire, each said cross member having a series of relatively deep notches for spacing the turns of wire of an inner series, each cross-arm having a longitudinal groove in its outer edge, an insulation strip mounted in said groove, said strip provided With notches in its inner edge for laterally spacing the turns of an outer series.

8. In a device of the kind described, cross members for spacing the turns of Wire, each said cross member having a series of relatively deep notches for spacing the turns of of an inner series, each cross-arm having a longitudinal groove in its outer edge, a second series of turns wound on the outer edges of said Ecross members, and a notched i1'i:- 4ulation strip mounted in said groove and securing the turns of the outer series in place.

In testimony whereof, I have hereunto set my hand, this 23rd day of May, 1925.

MARIUS MATHIESEN. 

